1. Field of the Invention
The present invention relates to a device for moving a support for shelves, cupboards, tables or similar along a path, which support is suspended on an arm that is pivotally connected to a base, for example a wall, in an axis of rotation at one end of the arm.
2. Description of the Related Art
Devices of this type are used chiefly to lower shelves and cupboards from a position high up on a wall to a position lower down in order to facilitate access by disabled persons, for example, to articles placed high up. A typical area of application is the raising and lowering of shelves in an overhead cupboard in a kitchen.
A number of such devices are known. Reference shall be made, for example, to NO-163 162, DE-1 554 464, DE-3 215 572, DE-3 914 307, DE-2 721 307, EP 242811, EP 661015, EP 402283, DE-3 635 592, DE 2 919 610, DE-3 433 137 and DE-2 524 406. The devices according to these publications function for the most part either in that the cupboard or shelves are guided vertically, or in some cases slantwise, on rails or by means of arms of parallelogram configuration. These raising and lowering devices are set to guide the cupboard/shelves along a fixed path, which in the case of the rail-guided devices is a straight line, in the case of the devices which make use of arms of parallelogram configuration it is a circular arc. The path which the cupboard/shelves follow is fixed once and for all when the device is installed.
With the known devices it is not possible to lower an overhead cupboard below the level of the kitchen counter. Rail guides running on the outside of the kitchen counter would not be practical as these would prevent normal use of the kitchen counter. Nor do the parallelogram-guided devices provide any possibility of lowering, for example, an overhead cupboard below the kitchen counter. The lowering facility is limited by the length of arms, which in turn is limited by the height of the ceiling or the depth of the cupboard. For many disabled persons this may be insufficient to enable them to reach the top shelves in the overhead cupboard.
The raising and lowering devices, which function with the aid having a arms of parallelogram configuration, have arms consisting of several links, which inevitably results in a certain slack and above all the danger of the arms "scissoring" the wrong way when the arms assume a position parallel to or almost parallel to one another. A second problem with the parallelogram mechanism is that when the sides (the arms) of the parallelogram approach one another a great moment of force is exerted on the drive mechanism. The drive mechanism must therefore be dimensioned so as to be very strong or, alternatively, the moment of force must be compensated by means of weights or springs. Since the moment of force varies greatly depending upon the weight of the shelves, the weight or springs will not be able to compensate satisfactorily.